Chip and Dale to help dig island airport tunnel

Geoffrey Wilson, president and CEO of Toronto Port Authority, speaks to the media during the announcement of the construction of an underwater tunnel to the island airport in Toronto Nov. 9, 2012. (Dave Abel/Toronto Sun)

More Coverage

Two 90-tonne Canadian-made tunnel boring machines called Chip and Dale, named after two cartoon chipmunks on the show Rescue Rangers, are getting set to rip through dirt and rocks in the next step toward building an underground walkway to the Toronto island airport.

In March, an excavator dug 70 feet below the surface. The borers will now begin digging seven 1.8-metre interlocking tunnel drifts in order to create an arched roof above the walkway and prevent water seeping into the area for construction crews.

“The tunnel operation will start using the two machines (two metres in diameter) and will be working simultaneously from the mainland to the island,” said Tony DiMillo, president of Technicore Underground, which has been contracted for this part of the project.

“Each tunnel (drift) will take approximately two weeks. Once the tunnel is excavated and shored, it then gets filled with concrete. It creates an actual shoring system from the earth above.”

Three of these tunnel drifts will carry city mains to the Toronto island.

When the drift work is completed, a separate excavator will create the main tunnel the passengers will walk through.

The tunnel is below about 10 metres of rock and river bed and 20 metres of water.